This invention is concerned with installation or removal of printed circuit cards into or from electronic equipment, without the need to suspend operation of the equipment.
Many pieces of electrical and electronic equipment are operated continuously during the installation or removal of printed circuit cards from the motherboard of the equipment. During such xe2x80x9chot swapping,xe2x80x9d it must be possible to access a card location without compromising safety, grounding, operation and electrical shielding of adjacent cards, and so forth. Cards usually stand generally perpendicularly to the motherboard and are connected to the motherboard by pins located on the edge of the card. Thus, there is a need to install or remove a card, without removing the enclosure of the equipment, by moving it in two distinct perpendicular directions: xe2x80x9cin then downxe2x80x9d in the case of insertion; xe2x80x9cup then outxe2x80x9d in the case of removal. The small sizes and close mounting of modular electronic equipment make this a difficult task in general, and lead to mis-alignment of installed cards in particular.
U.S. Pat. No. 5,815,377 (Lund et al.) addresses this situation with a card holder that both holds the card and slides on a card guide positioned within the enclosure, above the motherboard connector. Proper alignment with the enclosure during installation of the card guide is accomplished by (1) a rail that guides and holds the card holder from above, and (2) a pair of hooks that extend down from the guide and engage suitable features that prevent the card holder from additional motion. A horizontal cam arrangement below the motherboard moves the features (and thus, through the hooks, the card holder) to redirect horizontal force into vertical force, thus either installing the board into the motherboard connector, or removing it from the motherboard connector.
U.S. Pat. No. 5,868,585 (Barthel et al.) also show a card holder that holds the card and is suspended from an xe2x80x9cactuator barxe2x80x9d above the motherboard. Again, a horizontal cam arrangement, but located within the upper actuator bar instead of below the motherboard, redirects horizontal force into vertical force, thus either installing the board into the motherboard connector, or removing it from the motherboard connector.
One aspect of the invention is a method of installing or removing a printed circuit card during continuous operation of electronic equipment, and thus without the need to remove an upper part of the enclosure to gain access to the card for upward removal from a motherboard connector. The method relies on a generally immovable carrier that supports a movable actuator, which is coupled to a movable circuit card holder. Motion of the actuator is directed into perpendicular motion of the holder with respect to the motherboard. Thus, moving the actuator installs or removes the printed circuit card from its connector on the motherboard.
Other aspects of the invention are preferred embodiments that comprise a carrier positioned to be relatively immovable in the direction perpendicular to the motherboard. These embodiments also comprise a movable printed circuit card holder that slides along the carrier, perpendicularly towards and away from the motherboard. An actuator accessible from outside the equipment is movably supported by the carrier. The actuator and the holder are coupled together such that motion of the actuator is directed into perpendicular sliding motion of the holder. This either removes the card from its connector on the motherboard, or installs the card into the connector, depending on the direction of motion of the actuator.
One preferred embodiment of the actuator employs a sliding member having at least one angled slot coupled with force transfer tabs located on the card holder. Horizontal motion of the actuator produces perpendicular motion of the holder. Another preferred embodiment of the actuator comprises a rotatable shaft bearing at least one pinion gear engaged with a rack gear on the holder. Rotational motion of the shaft produces the perpendicular motion of the holder.
All aspects of the invention are particularly suitable for cards meeting the PCI standard, but this is not a requirement.